The newborn baby who was rescued by Chinese firefighters from a sewer pipe below a squat toilet has suffered "severe bruising" but is in a "stable condition" in hospital.

A tenant heard the baby's sounds in the public restroom of a residential building in Zhejiang province in eastern China on Saturday and notified authorities, according to the state-run news site Zhejiang News. A video of the two-hour rescue that followed was broadcast widely on Chinese news programmes and websites on Monday and yesterday.

The child - named Baby No. 59 from the number of his hospital incubator - was reported safe in a nearby hospital, and news of the rescue prompted an outpouring from strangers who came to the hospital with nappies, baby clothes, powdered milk and offers to adopt the child.

He is now healthy enough to leave the hospital, which has been paying his medical bills and accepting donations of clothes, baby formula and other gifts.

It was not immediately clear how the baby ended up in the pipe, but one police source in Jinhua claimed that the woman gave birth unexpectedly when she went to the lavatory on Saturday. She then reportedly phoned the landlord, claiming that she heard ''weird noises'' in the pipe.

''The woman was on the scene during the entire rescue process... and admitted [she was the mother] when we asked her,'' the source told Sky News. ''We need further investigations to find out if she had any malicious intentions.''

She is said to be in a serious condition because of complications caused by the delivery.

The baby was stuck in the L-joint of pipe with a diameter of about 3 inches.

The video shows rescuers sawing out a section of the pipe along a ceiling that apparently was just below the restroom. The rescuers then rushed that section of pipe to a hospital, were firefighters and medics alternately used pliers and saws to rip apart the L-joint and free the baby.

Despites the offers to adopt Baby No. 59, a doctor at the hospital said the boy would be handed over to social services if his parents do not claim him, Zhejiang News said.

Cases of abandoned babies are common in China, with young mothers and strict family planning rules often blamed. But Saturday's case provoked a furious response on Chinese social media sites, with hundreds of thousands of protests posted this week.

''The parents who did this have hearts even filthier than that sewerage pipe,'' wrote one user of the Twitter-like Weibo.

Another wrote: ''I can never accept or forgive the behaviour of dumping the baby with his placenta and umbilical cord attached into the toilet pipe.

''Can these people be called human beings? The animal to human ratio among the grown-ups is rising inexorably.''